lib/modfl.c

   1 /* Get signed integer and fractional parts of a floating-point number.
   2    Copyright (C) 2012-2024 Free Software Foundation, Inc.
   3
   4    This file is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU Lesser General Public License as
   6    published by the Free Software Foundation, either version 3 of the
   7    License, or (at your option) any later version.
   8
   9    This file is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 #include <config.h>
  18
  19 /* Specification.  */
  20 #include <math.h>
  21
  22 #if HAVE_SAME_LONG_DOUBLE_AS_DOUBLE
  23
  24 long double
  25 modfl (long double x, long double *iptr)
  26 {
  27   double integer_part;
  28   double fractional_part = modf (x, &integer_part);
  29   *iptr = integer_part;
  30   return fractional_part;
  31 }
  32
  33 #else
  34
  35 long double
  36 modfl (long double x, long double *iptr)
  37 {
  38   if (isfinite (x))
  39     {
  40       long double integer_part = truncl (x);
  41       *iptr = integer_part;
  42       return x - integer_part;
  43     }
  44   else
  45     {
  46       if (isinf (x))
  47         {
  48           *iptr = x;
  49           return 1.0L / x;
  50         }
  51       else /* isnanl (x) */
  52         {
  53           *iptr = x;
  54           return x;
  55         }
  56     }
  57 }
  58
  59 #endif